The objective of this study is to show that Raman spectroscopy can be used to evaluate the lipid and calcium salt contents of human peripheral arteries. We studied 167 segments of carotid and femoral artery wall in various pathological states. The Raman spectra from these samples could be accurately modeled. The resulting chemical concentrations were compared with the amounts of cholesterol and calcium mineral determined by histological evaluation by an experienced cardiovascular pathologist. Strong correlations between the spectroscopic measurements and the morphological findings were demonstrated, thus validating the applicability of the method to peripheral arteries. Raman spectroscopy can provide reliable histochemical information about peripheral, as well as coronary arteries. Such information may help identify individuals with rupture-prone plaques before the onset of symptoms, allowing aggressive and directed intervention. Accurate knowledge of the chemi cal composition of a lesion may also be useful in selecting the most appropriate treatment modality.